Topic 61: Operation Relevance

How can we tell what's relevant when we try to work out what other people mean? What can experiments tell us about how much we'll consider when puzzling out meaning? In this episode, we talk about relevance theory: how it can help us more scientifically approach relevance in our discussions, how it interacts with the rest of our understanding of the rules of conversations, and how we can play with relevance in experiments to make people more or less likely to behave in logical ways.

Quick Summary:

During our conversations, we routinely go beyond the pure semantic meanings of the sentences themselves, making our interpretations richer by adding in various kinds of extra implications. But how do we get to these ideas? Well, one hypothesis we've discussed before is Paul Grice's Communicative Principle, and its four basic maxims. But another proposal stems from the Maxim of Relevance, which just says "Be relevant", to build an alternative approach to pragmatics known as Relevance Theory. In Relevance Theory, listeners will only consider adding information to their interpretation if it's relevant to their interpretive task. And relevance is defined as a comparison of the relative effort needed to process an implicature, compared to the effect that it'll have on the interpretation. Low-effort, high-effect inferences are very likely to get computed, whereas the reverse most likely won't.

We can get a sense of how this works by looking at some experimental treatments of Relevance Theory, using the Wason Selection Task. In this task, a participant is given four cards, say two with numbers face up, like 6 and 7, and two with colours face up, like red and blue. They're then given a rule to verify by flipping over as many cards as necessary: all cards with 6's on them have red backs. It's clear that to check this rule, you need to flip the card with the 6 up over... but only about 10% of participants flip over the other required card, the blue card, to make sure it has no 6 on the back. Under Relevance Theory, this is argued to be because the processing needed to see why flipping the blue card over is important just gets too high-effort, and so people don't go that far. But by either making the need to flip the card require a lower effort or by making it higher effect, researchers have been able to push participants to flip over the right cards in a much higher number of cases. By making the extra flip more relevant, people's behaviour really does change!

Extra Materials:

In the episode, we focused on how the Communicative Principle of Relevance guides our comprehension of sentences, and how the inferences that we make about what people intend to communicate can depend on both the effort it takes for us to make those inferences, and the cognitive effects we think they might have.

Because we assume everything people say is optimally relevant, and because we know other people are going to make this same assumption about us, we craft our sentences to conform to this expectation. We try to make our statements relevant enough to process, while still matching them to our own abilities and preferences. And, so, it isn’t only our interpretations that are shaped by the ideas central to Relevance Theory, but our speech as well.

To test this idea, researchers conducted a series of speech production experiments, designed to see whether manipulating the context of a conversation could affect the overall relevance of different possible responses to a question, making each option more or less likely to be said.

In the first experiment, researchers approached strangers and asked them for the time. The basic assumption they made was that, generally, rounding to the nearest multiple of five maximized relevance, since these numbers are easier to manage than more precise ones, while still mostly achieving the same cognitive effect. To control for the possibility that subjects only ever rounded to the nearest multiple of five because they had an analog watch, which might have more to do with minimizing effort for the speaker than making the response more relevant for the hearer, they kept track of interactions involving digital watches too.

What they found was that both speakers with digital watches and speakers with analog watches rounded times. While the analogue watch group rounded the most (97% of the time), the digital watch group also made a point of rounding (57% of the time). Since this arguably requires more effort than simply reading off the exact time, we can tentatively conclude that speakers deliberately maximize the relevance of what they have to say.

To rule out the possibility that speakers wearing digital watches were rounding only because they didn’t want to commit to their being completely accurate, and not because they wanted to maximize relevance, another experiment created a context where accuracy was especially relevant: researchers made it clear they were trying to set their watch when asking for the time.

In this second experiment, subjects ended up rounding more when they were simply asked for the time out of the blue (94% of the time) and less when the context was deliberately manipulated to make the most relevant response the unrounded one (49% of the time). So, it looks like speakers were more relevant (by being more accurate) when context demanded it — suggesting again that when speaking, we really do follow the principles of Relevance Theory.

To solidify these findings, a third experiment was run. This time, researchers asked people for the time, but also told them they had an appointment to go to. The prediction was that when the researcher said the appointment was far away — say, in about half an hour — subjects ought to round more, since precision here isn’t super important. But when the researcher said the appointment was soon — say, within the next 15 minutes — subjects ought to be more likely to give the exact time, since rounding could be misleading, as minutes might make the difference between being on time and arriving late.

Sure enough, the “early” group rounded more often (97% of the time) than the “later” group (75% of the time). The difference there isn’t huge, but together with the other experiments, it further solidifies the idea that the presumption we make that speakers are being as relevant as they can be in a given context really is justified.

The information here was taken from Ira Noveck and Dan Sperber's book Experimental Pragmatics, particularly Chapter 7.

Discussion:

So how about it? What do you all think? Let us know below, and we’ll be happy to talk with you about Relevance Theory, how it differs from the Gricean view, and what it can tell us about people's behaviour. There’s a lot of interesting stuff to say, and we want to hear what interests you!